German kidnapped as fresh blast strikes Nigeria's Kano

Gunmen abducted a German engineer on Thursday in the Nigerian city of Kano, where yet another explosion struck fear among residents plagued by unprecedented violence blamed on an Islamist sect.

The kidnap victim was Edgar Raupach, working with a construction company on the outskirts of the northern city, said Kano police spokesman Magaji Majia.

The spokesman also reported the blast at a bus terminal, saying it caused no casualties.

"They came and handcuffed him and put him in the boot and zoomed away," Majia said, adding that the German engineer was attached to Dantata and Sawoe, a Nigerian construction company.

"All the major highways were blocked and even the neighbouring states were equally alerted," he said.

The kidnapping of foreigners is rare in northern Nigeria.

A senior Kano police official said earlier that some 200 people had been arrested, most of the them Chadian "mercenaries," following coordinated gun and bomb attacks that killed at least 185 people in the city last week.

Boko Haram, a shadowy Islamist group, claimed that assault, its deadliest yet in a series over recent months.

A Briton and an Italian engineer with an Italian construction company based in Nigeria were seized from their apartment last May by gunmen in the northwest on the border with Niger.

Video footage sent to Mauritania's Agence Nouakchott Informations, claimed that the captors belong to a Nigerian group inspired by Al-Qaeda.

On Thursday morning, tension had eased in Kano, a Muslim majority city, with a bustling main market and banks reopening for the first time since the deadly attacks last Friday, an AFP correspondent said.

But the calm was disrupted by a fresh explosion that targeted a bus terminal where members of the mainly Christian Igbo tribe board coaches headed to their home area in southeastern Nigeria.

Majia said the area was evacuated shortly after the blast, whose cause was not yet clear.

Nigeria's security services have faced intense criticism amid escalating Islamist violence in recent weeks, and on Thursday a police official said a huge sweep of arrests had already been carried out.

"We have arrested around 200 attackers and 80 percent of them are Chadians. They came in as mercenaries," the official said on condition of anonymity.

There were indications the Chadians had been paid to participate in the recent attacks attributed to Boko Haram, the source added.

Boko Haram has been blamed for scores of other attacks in Nigeria, mainly in the north, and security forces have long suspected it of smuggling arms into the country through the porous northeastern borders with Chad and Niger.

A UN report on regional security released on Wednesday said there was evidence suggesting the Nigerian group had Chadian members who had received training from Al-Qaeda's north Africa affiliate.

But a Nigeria specialist with the International Crisis Group (ICG) said it was unlikely the sect had such a high number of foreigners in its ranks.

"I was shocked to hear that myself. Personally, I don't believe it," said Kunle Amuwo of the ICG.

"We know some foreigners have been implicated and continue to be implicated, but that number is huge," he said, adding that, based on his research in the region, he believes most Boko Haram members are dejected Nigerian youths.

The police source who reported the Boko Haram arrests, also said that suspected members of the sect had reached out to the police for potential dialogue, with the emir of Kano, the area's top Muslim leader, as mediator.

Boko Haram initially said it was fighting for the creation of an Islamic state in deeply impoverished northern Nigeria and launched an uprising in 2009 that was put down by a brutal military assault.

The group went dormant for more than a year before re-emerging with attacks that have become increasingly sophisticated.

It is now believed to have a number of factions with differing aims, including some with political links and a hard-core Islamist cell.